These Are the Countries Where Air Pollution Is the Deadliest

New Delhi has been engulfed in smog for days. It’s an issue that arises in the Indian capital each year as smoke from illegal crop burning, vehicle exhaust emissions and construction dust fill the air, but health officials say the problem has intensified this year.

India isn’t the only nation that is adversely affected by rising levels of pollution, from contaminated water to dirty air. Pollution, which causes heart attacks, strokes, lung cancer and respiratory diseases, “is the largest environmental cause of disease and premature death in the world today,” according to an October study on the health effects of pollution in the The Lancet medical journal. Toxic exposure cost $4.6 trillion and caused 9 million premature deaths – 6.5 million just from air pollution – in 2015, the study estimated.

Check out the 10 countries listed with the highest mortality rates (per 100,000 people) associated with air pollution in 2016, according to data from UW’s Institute for Health Metrics and Evaluation. Urban areas are often particularly hard hit by air pollution.